The software company has filed its first official complaint to the European Commission, accusing Google of a “pattern of walling off content and data” on the internet to prevent other search engines from being able to compete effectively.

IN Technology

“Google itself wouldn’t exist if it didn’t have the ability to crawl the rest of the web,” said Brad Smith, Microsoft’s general counsel.

The complaint comes amid a broad investigation in Brussels into Google’s search and advertising practices, triggered by complaints from three companies last year, one of which is now a part of Microsoft.

The software company acknowledged the irony in its appeal to Brussels for support. It has often criticised European regulators’ handling of competition cases, accusing them of being overly influenced by complaints from competitors.

Mr Smith admitted that Microsoft had “not been shy” about expressing its views, but said: “The open investigation is in Europe, it made sense to go there.” He said that the software company had lobbied US regulators against Google in the past, including over its 2008 bid for Yahoo and a current probe into the acquisition of travel technology company ITA.

Google’s opponents are pressing the US Department of ­Justice to open the same sort of sweeping probe into Google as the Brussels one.

Microsoft’s decision to turn to Brussels is “entirely pragmatic”, said Keith Hylton, a professor at Boston University School of Law. “If they’re going to get punched, they’re going to punch back.” He said it was a “rational combative strategy” for US tech companies to use Europe’s antitrust machinery against each other but warned that they risked harming their collective interests in the long run.

Google said it was “not surprised” by Microsoft’s move, given that one of the software company’s subsidiaries was one of the original complainants. “For our part, we continue to discuss the case with the European Commission and we’re happy to explain to anyone how our business works,” it said.

Microsoft pointed publicly to six examples that it said showed that Google was abusing its dominant position in search, though its official, private complaint lists more than 20 cases in all.

They include an accusation that Google’s YouTube service cannot be fully indexed by a rival search engine such as Bing, and that Google unfairly restricts advertisers from exporting data about their campaigns on Google to rival advertising services.